Tube support and shield



Aug. 9, 1949. F. H. DRAKE 2,478,574

TUBE SUPPORT AND SHIELD Original Filed June 14, 1946 'llilll! Patented Aug. 9, 1 949 TUBE SUPPORT AND SHIELD Frederick Hales Drake, Boonton, N. J., asslgnor to Aircraft Radio Corporation, Boonton, N. J., a corporation of New Jersey Original application June 14, 1946, Serial No.- 676,682. Divided and this application October 10, 1947, Serial No. 779,172

7 Claims.

This invention relates to a tube support and shield, and more particularly to a shielded electrical housing having a removable closure which carries the socket for a vacuum tube.

The prior supports and shields for the tubes of electrical equipment operated at ultra high frequencies have not been entirely satisfactory as the shielded housings for the tubes were constructed with closures which could be removed only with the aid of screw drivers or other tools. The removal and replacement of. a defective tube required some little time when the appropriate tool was available and there was the possibility of mechanical damage to the equipment when attempts Were made to remove the closure by other tools.

Objects of the invention are to provide tube supports and shields in which the tube socket is carried by a closure that is readily removable from the shielding housing without the use of tools. A further object is to provide a shielded electrical housing having a removable closure which carries a socket for a vacuum tube, the mounting of the socket and the devices for securing the closure to the housing being such that the tube may be properly positioned within the housing without imposing any mechanical stresses upon either the tube or the socket.

These and otherobjects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawings in which:

Fig. 1 is an elevation, Withparts in. section, of a cavity resonator or ultra high frequency oscillator which includes a telescoped coupling embodying the invention;

Fig. 2 is an end elevation of the removable closure, as seen from the outer end and with the end cap removed;

Fig. 3 is a fragmentary elevation, with parts in section, of another housing and removable closure construction;

Fig. 4 is a larger scale elevation, with parts broken away, of the ball-bearing clamping nut; and

Fig. 5 is a fragmentary end view of the clamping nut.

In the drawings, the reference numeral I identifies the cylindrical shell of a resonator cavity having an end wall 2 which may be longitudinally adjustable through means; not shown, and an axially supported tube 3 which carries a split socket 4 for receiving the anode cap 5 of a vacuum tube 6 of the so-called lighthouse type. A resilient sleeve 1 within the shell I has an internal diameter for receiving, with a relatively snug fit, the metallic tube shell 8 which is connected electrically to the tube cathode and extends axially from the base 9 of the tube. A grid sleeve II] is telescoped over the control grid ring H to engage a grid leak connection, not shown, when the tube is in position within the cavity. The elements so far described may be of any desired form and construction as they form no part of the present invention.

I he other closure for the cylindrical cavity shell i has an inner section l2 which telescopes into the end of. the shell I which is axially split to provide a series of clamping fingers l3, and an outer section I4 of somewhat larger diameter which is internally threaded to receive an end cap I5 having diametrically disposed lugs [6 to which a straight edged. device may be applied to rotate the cap into closed position. The outer section [4 is provided with one or more threaded bosses l1 into which are threaded the metal shield tubes I8 of ferro-magnetic chokes, not shown, which surround the. terminal rods 19.

A tube socket 20 of the molded disk type extends across the inner end of the closure and is supported for limited angular and radial movement by its marginal flange which extends between the inturned flanges of the closure section l2 and of an anchoring sleeve 2!. The sleeve 2| fits snugly within the closure section 12 to which it is secured, when firmly pressed against the socket 20, by a number of circumferentially spaced spots of solder 22. The inturned flange 23 of the sleeve 2| has diametrically opposed projections 24 which interlock, with substantial circumferential and radial clearance, with recesses 25 in the lower. portion \of thesocket disk 20. The difierential heating and attendant differential expansion of the closure shell and the sleeve 2i during the soldering, operation result in a slight axial clearance, of the order of thousandths of an inch between the tube socket 20 and its supporting flanges, whichpermits' angular and transverse adjustment of the socket 20 but which prevents any substantial axial movement of the socket 20: and tube 6; The diameter of socket 28 is somewhat less than the inner diameter of the shell to permit some displacement of the socket 20 with respect to the supporting flanges but the adjustments are limited by the clearance between the. projections24 andthe walls of the notches 25.

Th6 end closure and tube mount are secured to the shell I of the cavity by a clamping member or nut 26 having a cylindrical and milled outer surface and an internally threaded inner end 21 for engagement with threads 28 on the cavity shell I adjacent the clamping fingers l3. The nut 26 is counterbored from its outer end and circumferentially grooved to receive a series of small balls 29 which are retained in the groove by the inturned end flange 30 of the nut. The fingers or strips 13 are of less external diameter than the threads 28 to provide clearance for the threaded section 21 of the nut and also to increase the flexibility of the fingers l3. The ends of the fingers 13 are beveled, preferably at an angle of about 30 to the axis of the shell I, and the balls 29 roll along these beveled surfaces when the nut 26 is threaded upon the shell I.

The apparatus is assembled by placing the nut .4 flange of the shell, and a sleeve secured to the cylindrical shell and having a flange cooperating with said inturned shell flange to secure said socket against axial movement with respect to said closure.

3. A closure as recited in claim 2, wherein the diameter ofthe socket is less than the inner diameter of the cylindrical shell, whereby radial 1 clearance is provided between said shell and said 26 upon the shell I and rotating it to engage the threads 28. The tube 6 is'placed in its socket 20, and the closure and tube are inserted within the shell I, and then advanced to seat the tube anode cap 5 fully within its socket 4. The tube 6 is not subjected to bending stresses as the slidingimounting of the tube socket permits sufficient transverse movement of the tube to compensate for such variations in dimensions or symmetry as arise in commercial manufacture. The nut 26 is then turned down by hand to force the balls 29 against the beveled ends of the fingers l3 to flex the fingers into firm clamping engagement with the sections l2 of the closure.

The mechanical connection of the closure and housing is rigid and the electrical shielding is complete. The closure may be removed from the housing without the use of tools by backing the nut 26 from the threads 28 to release the clamping pressure applied to the fingers l3.

The relative arrangement of the rigid shell and the clamping finger elements of the telescoped housing and closure members may of course be reversed, as'shown in Fig. 3, in which a cupshaped end closure l2 with clamping fingers I3 is telescoped over a housing shell I'. The clamping nut 26 with balls 29 is threaded upon the end closures 2! The invention may of course be employed for the mounting and shielding of various types of tubesother than the one herein illustrated, and the housing may or may not be constructed as a resonator cavity. a a r This application is a division of my copen ding application Serial No. 676,682, filed June 14, 1946, Telescoped couplings, in which are presented claims to the mechanical features of the illussaid closure for supporting a vacuum tube, the

socket having a marginal flange, and means including members on said closure and at opposite sides of said marginal flange supporting said socket on said closure for limited angular and transverse movement.

2, A closure for a shielded electrical housing; said closure comprising a cylindrical shell having an inturned flange, a tube socket having a marginal flange seated against said inturned socket.

4. A closure as recited in claim 2, wherein the circumferential portion of said socket is provided with notches, and the flange of said sleeve has projections extending into certain of said notches with circumferential clearance to permit limited angular movement of said socket with respect to said closure shell.

5. A shielded electrical housing comprising a metallic housing shell, a socket terminal within said shell for the anode cap of a vacuum tube, said housing shell having external threads near one end thereof and terminating beyond said threads in resilient fingers having sloping end surfaces, a metallic closur including a cylindrical shell telescoped within the slotted end of said housing shell and an end cap of metal removably secured across the outer end of said cylindrical shell, clamping means securing said closure against displacement with respect to said housing shell, said clamping means comprising a nut threaded upon said external threads of the housing shell and carrying an annular assembly of ball members for rolling engagement with the sloping end surfaces ofthe resilient fingers of the housing shell, the inner end of said cylindrical shell having an inturned flange, a tube socket having a circumferential flange, and a sleeve secured within said'cylindrical shell and having a flange cooperating with said inturned flange to secure said tube socket within and against axial movement with respect to the cylindrical shell.

6. A shielded electrical housing as recited in claim 5, wherein the diameter of the socket flange is less than the inner diameter of said cylindrical shell, whereby radial clearance is provided between the circumferential flange of said tube socket and said cylindrical shell for limited radial adjustment of said socket with respect to said cylindrical shell. 7

7. A shielded electrical housing as recited in claim 6 wherein the flange of said tube socket is provided with notches, and said sleeve has pro jections extending into said notches with circumferential clearance to permit limited angular movement of said tube socket with respect to said cylindrical shell. 1

FREDERICK HALES DRAKE.

BEFERYENCESV'CITED The following references file of this patent:

UNITED STATES PATENTS Spielman Feb. 24. 1948 are of record inthe 

